Cattleya rex is a species of epiphytic orchid of showy white flowers, native to montane forests in Peru and Bolivia.

[1][3] Flowers large and showy, up to 17 cm wide, with sepals and petals being cream-colored or ivory white, except the lip or labellum, which is colored with yellow, rose and red.

[2] James O'Brien described the species for the first time in 1890 from a live flowering plant collected in the area of Moyobamba, San Martín by Mr. Bungeroth and cultivated at L'Horticulture International, Brussels, by Mr. L.

[2][4] Cattleya rex is known from a few localities in the regions of San Martin and Puno in Peru and the department of La Paz in Bolivia.

[8] Cattleya rex requires a temperate climate (16 °C at night and 28 °C during the day) and good ventilation (a dark and enclosed environment will attract fungi or bacterial diseases).